Timing event generation circuit for wireless communication apparatus

ABSTRACT

A system or circuit for generating timing events for mobile communications includes fetching network parameters corresponding to a transmission configuration. The network parameters are used to program a set of programmable registers. The timing events then are generated based on the network parameters. The timing events enable a user equipment (UE) or a base station to operate in various transmission configurations.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of currently pending U.S.application Ser. No. 13/650,138 filed on Oct. 12, 2012, and assigned toFreescale Semiconductor, Inc.

BACKGROUND OF THE INVENTION

The present invention relates generally to mobile communications, and,more particularly, to a system for generating timing events in mobilecommunication network.

Recent mobile communication networks have been developed to operateaccording to various mobile telephony standards, viz., wideband codedivision multiple access (W-CDMA), narrowband CDMA (N-CDMA), globalsystem for mobile communications (GSM), and long term evolution (LTE).These different standards use different frame structures to countsub-frames in a frame, count slots in a sub-frame, count chips in aslot, and count symbols in a slot, and these differing frame structuresnecessitate the use of different timing event generation schemes.

Timing events usually are generated by a radio-frequency (RF) timer thatis integrated in an user equipment (UE) or a base station. The RF timergenerates the timing events using a hardware timing event generationlogic circuit. The base station starts transmission and reception basedon the timing events from the RF timer, and the UE transmits andreceives data from the base station based on these generated timingevents. Using a hardware timing event generation logic circuit causesthe UE or the base station to be compatible only with a single cellularnetwork. For example, a base station or UE that includes a hardwarecircuit connected to a GSM network will be compatible with the GSMnetwork alone and is not operable with other cellular networks.

The operation of a UE across multiple standards may be enabled with amulti-mode UE. However, manufacturing economical and ergonomicmulti-mode UEs has many challenges. Due to wide differences in base bandprocessing across different standards, hardware sharing inside amulti-mode UE is a difficult task, requiring integrating separatehardware components for each standard, which substantially increases theprice and size of the UE. Presently, there is no system to render thebase station compatible with multiple cellular networks. Thus, multiplebase stations are installed and maintained for operating in multiplecellular networks, which further increases operational costs.

Therefore, it would be advantageous to have a system and method forgenerating timing events in either or both a UE and a base station thatsupports multiple mobile telephony standards.

BRIEF DESCRIPTION OF THE DRAWINGS

The following detailed description of the preferred embodiments of thepresent invention will be better understood when read in conjunctionwith the appended drawings. The present invention is illustrated by wayof example, and not limited by the accompanying figures, in which likereferences indicate similar elements.

FIG. 1 is a schematic diagram illustrating a mobile communication systemin accordance with an embodiment of the present invention;

FIG. 2 is a schematic block diagram illustrating a RF timer inaccordance with an embodiment of the present invention;

FIG. 3 is a schematic block diagram illustrating programmable registersin the RF timer of FIG. 2 in accordance with an embodiment of thepresent invention;

FIG. 4 is a flow chart illustrating a method for generating timingevents by the RF timer of FIG. 2 in accordance with an embodiment of thepresent invention; and

FIG. 5 is a a schematic diagram illustrating a mobile communicationsystem in accordance with an embodiment of the present invention;

FIG. 6 is a diagram of a conventional frame structure of LTE TimeDivision Duplexing (TDD) mode; and

FIG. 7 is a schematic block diagram illustrating programmable registersin the RF timer of FIG. 2 in accordance with an embodiment of thepresent invention; and

FIG. 8 is a diagram of a frame structure for enhanced MultimediaBroadcast Multicast Service (eMBMS).

DETAILED DESCRIPTION OF THE INVENTION

The detailed description of the appended drawings is intended as adescription of the currently preferred embodiments of the presentinvention, and is not intended to represent the only form in which thepresent invention may be practiced. It is to be understood that the sameor equivalent functions may be accomplished by different embodimentsthat are intended to be encompassed within the spirit and scope of thepresent invention.

In an embodiment of the present invention, a RF timer for generatingtiming events to enable a wireless communication device to operate in aplurality of transmission configurations is provided. The wirelesscommunication device includes at least one of an user equipment (UE) anda base station. The RF timer includes a memory module for storing aplurality of sets of network parameters corresponding to the pluralityof transmission configurations. A plurality of programmable registersconfigured using at least one of the sets of network parameters iscoupled to the memory module. An event generation logic circuit, coupledto the plurality of programmable registers, generates the timing eventsbased on a first set of the network parameters corresponding to a firsttransmission configuration for enabling the wireless communicationdevice to operate in the first transmission configuration.

In another embodiment of the present invention, a wireless communicationdevice capable of operating in a plurality of transmissionconfigurations is provided. The wireless communication device includes aRF timer for generating a plurality of timing events. The RF timerincludes a memory module for storing a plurality of sets of networkparameters corresponding to the plurality of transmissionconfigurations. A plurality of programmable registers capable of beingconfigured using at least one of the sets of network parameters areconnected to the memory module. An event generation logic circuit,coupled to the plurality of programmable registers, generates theplurality of timing events based on a first set of the networkparameters corresponding to a first transmission configuration forenabling the wireless communication device to operate in the firsttransmission configuration.

In yet another embodiment of the present invention, a method forgenerating a plurality of timing events by a RF timer of a wirelesscommunication device to enable the wireless communication device tooperate in a plurality of transmission configurations is provided. Themethod includes storing a plurality of sets of network parameterscorresponding to the plurality of transmission configurations in amemory module of the RF timer. A plurality of programmable registers isprogrammed using a first set of the network parameters corresponding toa first transmission configuration. Thereafter, the plurality of timingevents are generated by the RF timer based on the first set of thetransmission configurations, to enable the wireless communication deviceto operate in the first transmission configuration.

Various embodiments of the present invention provide a system and methodfor generating timing events by a RF timer of a wireless communicationdevice to enable the wireless communication device to operate in aplurality of transmission configurations. The wireless communicationdevice may include a UE or a base station. The method includes storingsets of network parameters that correspond to multiple transmissionconfigurations, in a memory module of the RF timer. A set of networkparameters corresponding to a transmission configuration is used toprogram a set of programmable registers. The timing events are generatedbased on the network parameters used to program the set of programmableregisters, thereby enabling the UE or the base station to operate acrossmultiple transmission configurations of a cellular network, such as timedivision duplexing (LTE-TDD). When the RF timer of the present inventionis used in a base station, the base station can operate across multipletransmission configurations, which eliminates costs associated withinstalling and maintaining multiple base stations corresponding tomultiple transmission configurations. Similarly, when the RF timer isused in a UE, the UE can communicate across different transmissionconfigurations without the need for integrating separate hardware foreach transmission configuration. Thus, the cost and size of the UE isreduced considerably and challenges associated with the production ofmulti-mode UEs are significantly eliminated.

Referring now to FIG. 1, a schematic diagram illustrating a mobilecommunication system 100, in accordance with an embodiment of thepresent invention, is shown. The mobile communication system 100includes UE 102 and a plurality of base stations including first andsecond base stations 104 a and 104 b (collectively referred to as basestations 104). The UE 102 includes a RF timer 106.

The UE 102 communicates with the first and second base stations 104 aand 104 b based on timing events generated by the RF timer 106. In anembodiment of the present invention, the first and second base stations104 a and 104 b and the UE 102 are examples of wireless communicationdevices and communicate in different cellular networks according to atleast one of W-CDMA, N-CDMA, GSM, and LTE mobile telephony standards.The first and second base stations 104 a and 104 b are at least one oflegacy base stations, picocells, and femtocells. The RF timer 106 ispre-programmed to generate timing events corresponding to a preselectedcellular network. Thus, the RF timer 106 generates timing eventscorresponding to one of the W-CDMA, N-CDMA, GSM, and LTE networks andmakes the UE 102 compatible with more than one cellular network. In anembodiment of the present invention, the RF timer 106 is located insidea base station such as the first and second base stations 104 a and 104b. The RF timer 106 makes the base stations 104 compatible with themultiple cellular networks by generating the timing events correspondingto one of the above mentioned cellular networks.

Referring now to FIG. 2, a schematic diagram of the RF timer 106 inaccordance with an embodiment of the present invention is shown. The RFtimer 106 includes a memory module 202, a set of programmable registers204, and an event generation logic circuit 206.

The memory module 202 stores sets of network parameters corresponding tovarious cellular networks. In an embodiment of the present invention,the memory module 202 stores a lookup table (similar to Table-A, shownbelow) that includes sets of network parameters corresponding to variouscellular networks including N-CDMA, W-CDMA-FDD, LTE-FDD, LTE-TDD, andGSM. In various embodiments of the present invention, the networkparameters include a count of sub-frames in a frame, a count of slots ina sub-frame, a count of symbols in a slot, uplink (UL), downlink (DL),special slot (SP) slot attributes, downlink pilot time slot (DwPTS) anduplink pilot time slot (UpPTS) lengths. The programmable registers 204are configured using one of the sets of network parameters thatcorrespond to a preselected cellular network for which the timing eventsneed to be generated. For example, when the preselected cellular networkcorresponding to that for which the timing events need to be generatedis a GSM network, then corresponding network parameters are used forprogramming the programmable registers 204. Similarly, networkparameters corresponding to other cellular networks are used forprogramming the set of programmable registers 204.

TABLE A Network Network Mode Parameters NCDMA WCDMA-FDD LTE-FDD LTE-TDDGSM LEN 16 16 2048 + CP 2048 + CP 628 SYM_PER_SLOT 6 16 5, 6, 7 5, 6, 84, 8 TOTAL_LEN 128 256 15360 15361 130000 or 255000 UPPTS_LEN NA NA NA2191-5120  NA DWPTS_LEN NA NA NA 6592-26636 NA CHIPS_PER_SLOT 64 6415360 15360 5000 SLOT_PER_SUBFRM 2 10 2 2 51 or 26 SUBFRM_PER_FRM 16 1510 10 26 or 51 DLSLOT FFFFF FFFFF FFFFF FFE00 FFFFF ULSLOT FFFFF FFFFFFFFFF 000FF FFFFF SPSLOT 0 0 0 h00100 FFFFF

The programming of the programmable registers 204 includes storing thenetwork parameters into the programmable registers 204. Each networkparameter is stored in a programmable register 204 (see FIG. 3).

The event generation logic circuit 206 reads the network parametersstored in the programmable registers 202 and generates timing events inaccordance with the network parameters. The timing events includesignals for a wireless communication device (i.e., the UE 102 or thebase stations 104) that indicate boundaries of frames, sub-frames, andsymbols in a received or a transmitted signal. Such generation of timingevents is well known in the art, and therefore a detailed descriptionhas been omitted from the present description so as not to obfuscate theinvention.

Referring now to FIG. 3, a schematic diagram of the programmableregisters 204 in accordance with an embodiment of the present inventionis shown. The programmable registers 204 include a sub-frame-per-frameregister 302, a slot-per-sub-frame register 304, a chips-per-slotregister 306, a symbols-per-slot register 308, a plurality of symbollength registers 310, a plurality of uplink attribute registers 312, aplurality of downlink attribute registers 314, a plurality of specialattribute registers 316, a downlink pilot time register 318, an uplinkpilot time register 320, an uplink delay register 322, a downlink delayregister 324, an uplink configuration length register 326, and adownlink configuration length register 328.

The programmable registers 204 are located inside the RF timer 106 andthe RF timer 106 is located inside the wireless communication devicesuch as the UE 102 or the base stations 104. It will be understood bypersons skilled in the art that cellular communication allows the UE 102and the base stations 104 to transmit and receive data in the form offrames, in which each frame includes one or more sub-frames, eachsub-frame is divided into slots, and each slot includes symbols. Eachcellular network has a different count of sub-frames in a frame, slotsin a sub-frame, and symbols in a slot. For example, N-CDMA has 16sub-frames per frame, 2 slots per sub-frame, and 4 symbols per slot andW-CDMA has 15 sub-frames per frame, 10 slots per sub-frame, and 16symbols per slot. Further, when the UE 102 and the base stations 104communicate in a frequency-division multiplexing (FDD) mode, separatechannels are assigned for UL and DL communication. However, when the UE102 and the base stations 104 communicate in a time-divisionmultiplexing (TDD) mode, the same channel is used for UL and DLcommunication and in the role of the channel as a UL or DL channelalters every fixed time period. Thus, a slot will be a UL slot for a ULcycle and a DL slot for a DL cycle. Further, when the slots transitionfrom DL to UL, a time gap in the form of a SP slot is inserted toprevent symbols at the boundary of the last DL and first UL slots frominterfering. Therefore, each slot has UL, DL and SP slot attributes toindicate whether a slot is a UL, DL, or SP slot, respectively. When theUE 102 operates in LTE-TDD and W-CDMA cellular networks, specialsub-frames are inserted for which DwPTS and UpPTS lengths need to beconfigured. The parameters associated with a cellular network, viz.,count of sub-frames in a frame, count of slots in a sub-frame, count ofsymbols in a slot, UL, DL, SP slot attributes, DwPTS and UpPTS lengths,and the like are collectively referred to as network parameters.

The network parameters are used to program the programmable registers204 to configure the UE 102 to operate in a preselected cellularnetwork. For example, the sub-frame-per-frame register 302 stores thesub-frames in a frame count, the slot-per-sub-frame register 304 storesthe slots in a sub-frame count, the chips-per-slot register 306 storesthe chips in a slot count, the symbols-per-slot register 308 stores thesymbols in a slot count, the symbol length registers 310 store thesymbol lengths of the symbols, the plurality of uplink attributeregisters 312 store the uplink slot attributes of corresponding slots,the plurality of downlink attribute registers 314 store the downlinkslot attributes of the corresponding slots, the plurality of specialattribute registers 316 store the special slot attributes of thecorresponding slots, the downlink pilot time register 318 stores DwPTSlength, the uplink pilot time slot register 320 stores UpPTS length, theuplink delay register 322 stores the uplink delay, the downlink delayregister 324 stores the downlink delay, the uplink configuration lengthregister 326 stores the uplink configuration length, and the downlinkconfiguration length register 328 stores the downlink configurationlength. It will be understood by a person skilled in the art that the RFtimer 106 need not include all of the programmable registers 204mentioned above and may be customized to include a select number of theprogrammable registers 204 based on the desired operating functionalityof the UE 102.

Referring now to FIG. 4, a flow chart 400 illustrating a method forgenerating timing events by the RF timer 106 to enable a wirelesscommunication device to operate in multiple cellular networks inaccordance with an embodiment of the present invention is shown.

At step 402, network parameters that correspond to various cellularnetworks are stored in a lookup table in the memory module 202. Forexample, the lookup table shown above as Table-A includes networkparameters corresponding to N-CDMA, W-CDMA-FDD, LTE-FDD, LTE-TDD, andGSM. At step 404, the programmable registers 204 are programmed usingnetwork parameters that correspond to the cellular network for whichtiming events are to be generated. The network parameters are fetchedfrom the lookup table. The programming of the programmable registers 204includes storing the network parameters in the programmable registers204. At step 406, timing events are generated by the event generationlogic circuit 206 based on the network parameters stored in theprogrammable registers 204, which enable the operation of the wirelesscommunication device (the UE 102 or the base stations 104), in thecellular network corresponding to which the programmable registers 204are programmed. The timing events indicate boundaries of frames,sub-frames, symbols, and the like in a received or a transmitted signal.In an embodiment of the present invention, the RF timer 106 may belocated inside the base stations 104 or the UE 102.

Referring now to FIG. 5, a schematic diagram illustrating a mobilecommunication system 500 in accordance with an embodiment of the presentinvention is shown. The mobile communication system 500 includes a userequipment (UE) 502 and a base station 504 within a cell 506. The basestation 504 receives uplink information from the UE 502 through anuplink 508 and sends downlink information to the UE 502 through adownlink 510. The base station 504 includes the RF timer 106.

The base station 504 communicates with the UE 502 based on timing eventsgenerated by the RF timer 106. The timing events are generated accordingto a frame structure of the mobile communication system 500.

Referring to FIG. 6, in a frame structure of LTE Time Division Duplexing(TDD) mode, as is known in the art, a radio frame of length 10 ms has 10sub-frames indexed from sub-frame #0 to sub-frame #9, each sub-frame has2 slots indexed slot #0 and slot #1, and each slot has of m symbolsindexed from symbol #0 to symbol #m. Therefore the radio frame has 20slots indexed from S0 to S19. A special sub-frame, such as sub-frame #1here, has three fields Downlink Pilot Time Slot (DwPTS), Guard Period(GP) and Uplink Pilot Time Slot (UpPTS). Sub-frames used for uplinktransmission, downlink transmission or special purpose are configuredaccording to uplink-downlink configurations listed in Table-B where, foreach sub-frame in a radio frame, “D” denotes the sub-frame is reservedfor downlink transmissions, “U” denotes the sub-frame is reserved foruplink transmissions and “S” denotes a special sub-frame with the threefields DwPTS, GP and UpPTS.

TABLE - B Uplink-downlink configurations Uplink- Downlink- downlinkto-Uplink config- Switch-point Sub-frame number uration periodicity 0 12 3 4 5 6 7 8 9 0 5 ms D S U U U D S U U U 1 5 ms D S U U D D S U U D 25 ms D S U D D D S U D D 3 10 ms D S U U U D D D D D 4 10 ms D S U U D DD D D D 5 10 ms D S U D D D D D D D 6 5 ms D S U U U D S U U D

The length of DwPTS and UpPTS is given by TABLE-C subject to the totallength of DwPTS, GP and UpPTS being equal to 1 ms.

TABLE - C Configuration of special sub-frame (lengths of DwPTS/GP/UpPTS)Normal cyclic prefix in downlink Extended cyclic prefix in downlinkUpPTS UpPTS Normal Extended Normal Extended Special sub- cyclic cycliccyclic cyclic frame prefix in prefix in prefix in prefix inconfiguration DwPTS uplink uplink DwPTS uplink uplink 0  6592 · T_(s)2192 · T_(s) 2560 · T_(s)  7680 · T_(s) 2192 · T_(s) 2560 · T_(s) 119760 · T_(s) 20480 · T_(s) 2 21952 · T_(s) 23040 · T_(s) 3 24144 ·T_(s) 25600 · T_(s) 4 26336 · T_(s)  7680 · T_(s) 4384 · T_(s) 5120 ·T_(s) 5  6592 · T_(s) 4384 · T_(s) 5120 · T_(s) 20480 · T_(s) 6 19760 ·T_(s) 23040 · T_(s) 7 21952 · T_(s) 12800 · T_(s) 8 24144 · T_(s) — — —9 13168 · T_(s) — — —

In LTE TDD mode, different symbol lengths can be used between uplink anddownlink transmissions, and between UpPTS and DwPTS in specialsub-frames according to different configurations.

Referring back to FIG. 2, in a preferred embodiment of the presentinvention, the memory module 202 of the RF timer 106 further storeslookup tables (similar to Table-B and C, shown above) that includes setsof network parameters corresponding to various transmissionconfigurations. In various embodiments of the present invention, thenetwork parameters include at least one of sub-frames in a frame count,slots in a sub-frame count, symbols in a slot count, normal symbollength, alternate symbol length, DwPTS length, UpPTS length, uplinksub-frame attribute, downlink sub-frame attribute, special slotattribute, uplink configuration length, and downlink configurationlength in accordance with an operation standard of a cellular network.The programmable registers 204 are configured using one of the sets ofnetwork parameters that correspond to a preselected transmissionconfiguration for which the timing events need to be generated.

Referring now to FIG. 7, a schematic diagram of a programmable registers204′ in accordance with an embodiment of the present invention is shown.The programmable registers 204′ include an uplink-normal-symbol-per-slotregister UL_NORM_SYM_PER_SLOT 702 for storing the number of normalsymbols in an uplink slot, a downlink-normal-symbol-per-slot registerDL_NORM_SYM_PER_SLOT 704 for storing the number of normal symbols indownlink slot, an uplink-alternate-symbol-per-slot registerUL_ALT_SYM_PER_SLOT 706 for storing the number of alternate symbols inan uplink slot and a downlink-alternate-symbol-per-slot registerDL_ALT_SYM_PER_SLOT 708 for storing the number of alternate symbols indownlink slot. The programmable registers 204 also include a pluralityof symbol length registers, such as an uplink normal symbol lengthregister UL_NORM_SYM_LEN 710, a downlink normal symbol length registerDL_NORM_SYM_LEN 712, an uplink alternate symbol length registerUL_ALT_SYM_LEN 714 and a downlink alternate symbol length registerDL_ALT_SYM_LEN 716, where each symbol length register stores acorresponding symbol length. The programmable registers 204 furtherinclude a plurality of attribute registers, such as a plurality ofuplink attribute registers UL_SLOT_ATTR 718 for storing the uplink slotattributes of corresponding slots, a plurality of downlink attributeregisters DL_SLOT_ATTR 720 for storing the downlink slot attributes ofthe corresponding slots, a plurality of special slot attribute registersSP_SLOT_ATTR 722 for storing the special slot attributes of thecorresponding slots, and a plurality of slot configuration registers,such as an alternate uplink slot configuration register ALT_UL_SLOT_CFG724 for indicating uplink slots with alternate symbols and an alternatedownlink slot configuration register ALT_DL_SLOT_CFG 726 for indicatingdownlink slots with alternate symbols. As the alternate uplink slotconfiguration register ALT_UL_SLOT_CFG 724 and the alternate downlinkslot configuration register ALT_DL_SLOT_CFG 726 denote if a sub-frameuses normal or extended symbol, they can also be used to indicate if theuplink part of a special sub-frame (UpPTS) or downlink part of a specialsub-frame (DwPTS) uses normal or alternate symbols. Therefore, there isno need for an extra alternate special slot configuration register. Theplurality of symbol length registers, attribute registers and slotconfiguration registers allow the RF timer 106 to change symbol lengthsof different slots in one radio frame at run time without stopping RFtimer 106.

For example, when the base station 506 communicates with the UE 504 inLTE TDD mode based on the uplink-downlink configuration 3 in TABLE-B andspecial sub-frame configuration 0 in TABLE-C, the programmable registers204′ are programmed as:

UL_NORM_SYM_PER_SLOT=DL_NORM_SYM_PER_SLOT=7;

UL_ALT_SYM_PER_SLOT=DL_ALT_SYM_PER_SLOT=6;

UL_NORM_SYM_LEN=DL_NORM_SYM_LEN=FFT Length+Normal Cyclic Prefix Length;

UL_ALT_SYM_LEN=DL_ALT_SYM_LEN=FFT Length+Extended Cyclic Prefix Length;

UL_SLOT_ATTR[S0, . . . S3]=0, UL_SLOT_ATTR[S4, . . . S9]=1,UL_SLOT_ATTR[S10, . . . S19]=0;

DL_SLOT_ATTR[S0, S1]=1, DL_SLOT_ATTR[S2, . . . S9]=0, DL_SLOT_ATTR[S10,. . . S19]=1;

SP_SLOT_ATTR[S0, S1]=0, SP_SLOT_ATTR[S2, S3]=1, SP_SLOT_ATTR[S4, . . .S19]=1;

ALT_UL_SLOT_CFG[S0, . . . S2]=0, ALT_UL_SLOT_CFG[S3]=1,ALT_UL_SLOT_CFG[S4, . . . S19]=0;

ALT_DL_SLOT_CFG=0,

where the register values can be refreshed at radio frame boundaries.

FIG. 8 shows a diagram of a frame structure for enhanced MultimediaBroadcast Multicast Service (eMBMS) in LTE Frequency Division Duplexing(FDD) mode. A radio frame of length 10 ms has 10 sub-frames indexed fromSF #0 to SF #9, each sub-frame has 2 slots including 12 symbols indexedfrom Sym #0 to Sym #11. In LTE FDD mode, sub-frames SF #1-#3 and #6-#8are allowed to be configured as Multicast Broadcast Single FrequencyNetwork (MBSFN) sub-frames, and in each MBSFN sub-frame, the first oneor two symbols Sym #0 and #1 are unicast symbols used for unicast commonsignal and control channels, therefore with extended cyclic prefix. Therest non-unicast symbols in the MBSFN sub-frame are symbols with normalcyclic prefix configured for multi-cell transmission with MBSFNReference Signal (RS) and data. As shown in FIG. 8, a gap between thelast unicast symbol (Sym #0 or Sym #1) and the first non-unicast symbol(Sym #2 or Sym #3) of the non-unicast symbols is filled with padding.Similarly, in LTE TDD mode, sub-frames SF #3-#4 and #7-#9 are allowed tobe configured as Multicast Broadcast Single Frequency Network (MBSFN)sub-frames, which is not shown here.

Referring back to FIG. 7, the programmable registers 204′ furtherincludes a MBSFN slot configuration register MBSFN_SLOT_CFG 728 forindicating MBSFN sub-frames in the radio frame, and a unicast symbolnumber register MBSFN_NUM_SYM 730 for indicating unicast symbols in aMBSFN sub-frame. For example, if only the first symbol in the MBSFNsub-frame is a unicast symbol, the unicast symbol number registerMBSFN_NUM_SYM 730 is programmed as 0, and if the first two symbols inthe MBSFN sub-frame are unicast symbols, the unicast symbol numberregister MBSFN_NUM_SYM 730 is programmed as 1. Therefore, the gapbetween a unicast symbol and a non-unicast symbol in the MBSFN sub-framedue to different cyclic prefix lengths is managed.

Table-D shows a set of network parameters corresponding to eMBMStransmission stored in the memory module 202. In Table-D, sub-frame SF#1 is configured as the MBSFN sub-frame.

TABLE D Configuration of radio frame in eMBMS Parameter LTE-FDD(20 MHz)UL_NORM_SYM_LEN 2048 + NormalCP DL_NORM_SYM_LEN 2048 + NormalCPUL_ALT_SYM_LEN 2048 + ExtendedCP DL_ALT_SYM_LEN 2048 + ExtendedCPUL_NORM_SYM_PER_SLOT 7 DL_NORM_SYM_PER_SLOT 7 UL_ALT_SYM_PER_SLOT 6DL_ALT_SYM_PER_SLOT 6 UPPTS_LEN NA DWPTS_LEN NA CHIPS_PER_SLOT 15360SLOT_PER_SUBFRM 2 SUBFRM_PER_FRM 10 UL_SLOT_ATTR FFFFF DL_SLOT_ATTRFFFFF SP_SLOT_ATTR 0 ALT_UL_SLOT_CFG 0x00000 ALT_DL_SLOT_CFG 0x00000MBSFN_SLOT_CFG 0x0000C MBSFN_NUM_SYM 2

For example, when the base station 506 communicates with the UE 504 ineMBMS LTE FDD mode, the programmable registers 204′ are programmed as:

UL_NORM_SYM_PER_SLOT=DL_NORM_SYM_PER_SLOT=7;

UL_ALT_SYM_PER_SLOT=DL_ALT_SYM_PER_SLOT=6;

UL_NORM_SYM_LEN=DL_NORM_SYM_LEN=FFT Length+Normal Cyclic Prefix Length;

UL_ALT_SYM_LEN=DL_ALT_SYM_LEN=FFT Length+Extended Cyclic Prefix Length;

UL_SLOT_ATTR[S0, . . . S19]=1;

DL_SLOT_ATTR[S0, . . . S19]=1;

SP_SLOT_ATTR[S0, . . . S19]=0;

ALT_UL_SLOT_CFG[S0, . . . S19]=0;

ALT_DL_SLOT_CFG[S0, . . . S19]=0;

MBSFN_SLOT_CFG[S0, S1, S4, . . . S19]=0, MBSFN_SLOT_CFG[S2, S3]=1;

MBSFN_NUM_SYM=1;

where the register values can be refreshed at radio frame boundaries.

The event generation logic circuit 206 of the RF time 106 reads thenetwork parameters stored in the programmable registers 202 andgenerates timing events in accordance with the network parameters. Thetiming events include signals for a wireless communication device (i.e.,the UE 502 or the base stations 504) that indicate boundaries of frames,sub-frames, and symbols in a received or a transmitted signal.Therefore, different symbol lengths in downlink and uplink transmissionsare supported and can be dynamically changed at run time. Suchgeneration of timing events is well known in the art, and therefore adetailed description has been omitted from the present description so asnot to obfuscate the invention.

While various embodiments of the present invention have been illustratedand described, it will be clear that the present invention is notlimited to these embodiments only. Numerous modifications, changes,variations, substitutions, and equivalents will be apparent to thoseskilled in the art, without departing from the spirit and scope of thepresent invention, as described in the claims.

The invention claimed is:
 1. A radio-frequency (RF) timer for generatinga plurality of timing events to enable a wireless communication deviceto operate in a plurality of transmission configurations, wherein thewireless communication device transmits and receives data in a pluralityof frames, wherein each frame includes a plurality of sub-frames, eachsub-frame includes a plurality of slots, and each slot includes aplurality of symbols, wherein the wireless communication device includesat least one of a user equipment (UE) and a base station, the RF timercomprising: a memory module for storing a plurality of sets of networkparameters corresponding to the plurality of transmissionconfigurations, wherein a set of network parameters includes at leastone of sub-frames in a frame count, slots in a sub-frame count, symbolsin a slot count, normal symbol length, alternate symbol length, downlinkpilot time slot (DwPTS) length, uplink pilot time slot (UpPTS) length,uplink sub-frame attribute, downlink sub-frame attribute, special slotattribute, uplink configuration length, and downlink configurationlength in accordance with an operation standard of a cellular network; aplurality of programmable registers, coupled to the memory module, thatare configurable using at least one of the sets of network parameters,wherein the plurality of programmable registers includes at least one ofan alternate uplink slot configuration register for indicating uplinkslots with alternate symbols and an alternate downlink slotconfiguration register for indicating downlink slots with alternatesymbols; and an event generation logic circuit, coupled to the pluralityof programmable registers, for generating the plurality of timing eventsbased on a first set of the network parameters corresponding to a firsttransmission configuration of the plurality of transmissionconfigurations for enabling the wireless communication device to operatein the first transmission configuration.
 2. The RF timer of claim 1,wherein the plurality of programmable registers further includes a MBSFNslot configuration register for indicating MBSFN sub-frames, and a MBSFNsymbol number register for indicating unicast symbols in a MBSFNsub-frame.
 3. The RF timer of claim 1, wherein the plurality ofprogrammable registers are refreshed at radio frame boundaries.
 4. TheRF timer of claim 1, wherein the plurality of transmissionconfigurations are configured for at least one of time-division duplex(TDD) mode and enhanced Multimedia Broadcast Multicast Service (eMBMS).5. The RF timer of claim 1, wherein the plurality of programmableregisters includes at least one of: a normal-symbol-per-slot registerfor storing the number of normal symbols in a slot; analternate-symbol-per-slot register for storing the number of alternatesymbols in a slot; a plurality of symbol length registers, wherein eachsymbol length register stores a corresponding symbol length; a pluralityof uplink attribute registers for storing the uplink slot attributes ofcorresponding slots; a plurality of downlink attribute registers forstoring the downlink slot attributes of the corresponding slots; and aplurality of special slot attribute registers for storing the specialslot attributes of the corresponding slots.
 6. The RF timer of claim 1,wherein the plurality of slots are synchronized using a timing referencethat is common between the wireless communication device and a cellularnetwork.
 7. The RF timer of claim 6, wherein the timing reference is atleast one of pulse-per-second signal from a global positioning system(GPS) satellite, trigger input from IEEE 1588 standard protocol, andtiming reference from a cellular network.
 8. A wireless communicationdevice capable of operating in a plurality of transmissionconfigurations, wherein the wireless communication device transmits andreceives data in a plurality of frames, wherein each frame includes aplurality of sub-frames, each sub-frame includes a plurality of slots,and each slot includes a plurality of symbols, the wirelesscommunication device comprising: a radio-frequency (RF) timer forgenerating a plurality of timing events, wherein the RF timer comprises:a memory module for storing a plurality of sets of network parameterscorresponding to the plurality of transmission configurations, wherein aset of network parameters includes at least one of sub-frames in a framecount, slots in a sub-frame count, symbols in a slot count, normalsymbol length, alternate symbol length, downlink pilot time slot (DwPTS)length, uplink pilot time slot (UpPTS) length, uplink sub-frameattribute, downlink sub-frame attribute, special slot attribute, uplinkconfiguration length, and downlink configuration length in accordancewith an operation standard of a cellular network; a plurality ofprogrammable registers, coupled to the memory module, that areconfigurable using at least one of the sets of network parameters,wherein the plurality of programmable registers includes at least one ofan alternate uplink slot configuration register for indicating uplinkslots with alternate symbols and an alternate downlink slotconfiguration register for indicating downlink slots with alternatesymbols; and an event generation logic circuit, coupled to the pluralityof programmable registers, for generating the plurality of timing eventsbased on a first set of the network parameters corresponding to a firsttransmission configuration of the plurality of transmissionconfigurations for enabling the wireless communication device to operatein the first transmission configuration.
 9. The wireless communicationdevice of claim 8, wherein the plurality of programmable registersfurther includes a MBSFN slot configuration register for indicatingMBSFN sub-frames, and a MBSFN symbol number register for indicatingunicast symbols in a MBSFN sub-frame.
 10. The wireless communicationdevice of claim 8, wherein the plurality of programmable registers arerefreshed at radio frame boundaries.
 11. The wireless communicationdevice of claim 8, wherein the plurality of transmission configurationsare configured for at least one of time-division duplex (TDD) mode andenhanced Multimedia Broadcast Multicast Service (eMBMS).
 12. Thewireless communication device of claim 8, wherein the plurality ofprogrammable registers includes at least one of: anormal-symbol-per-slot register for storing the number of normal symbolsin a slot; an alternate-symbol-per-slot register for storing the numberof alternate symbols in a slot; a plurality of symbol length registers,wherein each symbol length register stores a corresponding symbollength; a plurality of uplink attribute registers for storing the uplinkslot attributes of corresponding slots; a plurality of downlinkattribute registers for storing the downlink slot attributes of thecorresponding slots; and a plurality of special slot attribute registersfor storing the special slot attributes of the corresponding slots. 13.The wireless communication device of claim 8, wherein the plurality ofslots are synchronized using a timing reference that is common betweenthe wireless communication device and a cellular network.
 14. Thewireless communication device of claim 13, wherein the timing referenceis at least one of pulse-per-second signal from a global positioningsystem (GPS) satellite, trigger input from IEEE 1588 standard protocol,and timing reference from a cellular network.
 15. A method forgenerating a plurality of timing events by a radio-frequency (RF) timerof a wireless communication device to enable the wireless communicationdevice to operate in a plurality of transmission configurations, whereinthe wireless communication device transmits and receives data in aplurality of frames, wherein each frame includes a plurality ofsub-frames, each sub-frame includes a plurality of slots, and each slotincludes a plurality of symbols, the method comprising: storing aplurality of sets of network parameters corresponding to the pluralityof transmission configurations in a memory module of the RF timer,wherein a set of network parameters includes at least one of sub-framesin a frame count, slots in a sub-frame count, symbols in a slot count,normal symbol length, alternate symbol length, downlink pilot time slot(DwPTS) length, uplink pilot time slot (UpPTS) length, uplink sub-frameattribute, downlink sub-frame attribute, special slot attribute, uplinkconfiguration length, and downlink configuration length in accordancewith an operation standard of a cellular network; programming aplurality of programmable registers in the RF timer using a first set ofthe network parameters corresponding to a first transmission mode of theplurality of transmission configurations, wherein the plurality ofprogrammable registers includes at least one of an alternate uplink slotconfiguration register for indicating uplink slots with alternatesymbols and an alternate downlink slot configuration register forindicating downlink slots with alternate symbols; and generating theplurality of timing events by the RF timer based on the first set of thenetwork parameters to enable wireless communication device to operate inthe first transmission mode.
 16. The method of claim 15, wherein theplurality of programmable registers further includes a MBSFN slotconfiguration register for indicating MBSFN sub-frames, and a MBSFNsymbol number register for indicating unicast symbols in a MBSFNsub-frame.
 17. The method of claim 15, wherein the plurality ofprogrammable registers includes at least one of: anormal-symbol-per-slot register for storing the number of normal symbolsin a slot; an alternate-symbol-per-slot register for storing the numberof alternate symbols in a slot; a plurality of symbol length registers,wherein each symbol length register stores a corresponding symbollength; a plurality of uplink attribute registers for storing the uplinkslot attributes of corresponding slots; a plurality of downlinkattribute registers for storing the downlink slot attributes of thecorresponding slots; and a plurality of special slot attribute registersfor storing the special slot attributes of the corresponding slots.